1. Field of the Invention
The present invention relates to an optical character recognition system for identifying characters printed, typed or handwritten on a sheet or card, which utilizes a one dimensional array of photo-sensitive elements and allows manual scanning of the data characters by means of a hand-held sensing device.
2. Description of the Prior Art
Heretofore, readout devices for typed or handwritten characters have usually utilized a complicated and costly scanning apparatus involving a flying spot scanning tube and/or a large number of register stages. Such systems typically employ a pattern matching technique for character recognition. Therefore, when an electrical character pattern obtained by converting a scanned character into corresponding electrical signals and storing them in a shift register is skewed or deviated in a lateral or vertical direction, or the respective adjacent character patterns are irregularly enlarged or reduced in a vertical or lateral direction, from their standard positions, then character recognition becomes impossible. Before such recognition, it has thus been necessary to perform a complicated preprocessing treatment to render the character inclination, size, and position as close to standard criteria as possible.
Even with such preprocessing treatment, character recognition is still impossible when the vertical tilt of the character and/or the horizontal scanning speed is beyond a certain tolerance level. For these reasons, a complicated scanning process using a flying-spot scanner and a precise sheet feeding mechanism such as a tag feeding mechanism to stabilize the feeding speed and direction has been required, resulting in a very expensive readout system.
In order to improve such defects of conventional systems a manual type of character recognition system has been developed, as disclosed in U.S. Pat. No. 3,947,817. Such system uses two dimensional arrays of photosensitive elements incorporated in a hand-held scanning device for scanning a data character printed on, for example, a tag. This system still involves a matrix of photosensitive elements, however, and performs a pattern-to-pattern comparison, whereby the processing hardware associated with the scanning device is relatively complicated and expensive.